Adsorption of Co 2+ and Cr 3+ in Industrial Wastewater by Magnesium Silicate Nanomaterials.

In this paper, two flower-like magnesium silicate nanomaterials were prepared. These and another two commercial magnesium silicate materials were characterized using a scanning electron microscope, the N 2 adsorption-desorption method, and other methods. The structure-activity relationship between the adsorption performance of these four magnesium silicate materials and their specific surface area, pore size distribution, and pore structure was compared. The results showed that the 3-FMS modified by sodium dodecyl sulfonate (SDS) had the largest specific surface area and pore size, the best adsorption performance, and the largest experimental equilibrium adsorption capacity ( q e,exp ) for Co 2+ , reaching 190.01 mg/g, and Cr 3+ , reaching 208.89 mg/g. The adsorption behavior of the four materials for Co 2+ and Cr 3+ both fitted the pseudo-second-order kinetic model and Langmuir adsorption model, indicating that chemical monolayer uniform adsorption was the dominant adsorption process. Among them, the theoretical adsorption capacity ( q m ) of 3-FMS was the highest, reaching 207.62 mg/g for Co 2+ and 230.85 mg/g for Cr 3+ . Through further research, it was found that the four materials mainly removed Co 2+ and Cr 3+ through electrostatic adsorption, surface metal ions (Mg 2+ ), and acidic groups (-OH and -SO 3 H) exchanging with ions in solution. The adsorption performance of two self-made flower-like magnesium silicate materials for Co 2+ and Cr 3+ was superior to that of two commercial magnesium silicates.